Whether you didn't know you had a balance due or you simply couldn't afford to pay it, an unpaid dentist bill can have debt collectors seeking payment from you. When the debt is placed in collections, it becomes a public record that appears on your credit report. How an unpaid dentist bill might affect your FICO score depends on which FICO version a lender uses and how much you originally owed.
FICO Score Versions
The FICO Score 8 system disregards small debts when figuring your credit score if they were originally less than $100. If a potential lender selects this scoring model and your unpaid dentist bill started at less than this amount, FICO ignores it and it won't affect your credit score. The FICO 9 model decreases the amount of weight placed on unpaid medical bills, so even if your unpaid dentist bill is more than $100, it won't impact your score as much as it would with earlier FICO models. Many lenders still use the earlier FICO versions, however, according to U.S. News & World Report.
Your Payment History
Thirty-five percent of your credit score is calculated based on your payment history, so if your unpaid dentist bill is included in the calculations, this is going to hurt your score. The impact on your credit score depends on how late you are on payments, the size of the debt and how recently the debts occurred. The FICO score also looks at how many delinquent accounts you have -- the more you have, the worse your score will be. If you have only one unpaid dentist bill, your score will fare better than if you have multiple past-due accounts.
Size of Debt
The size of your unpaid bill also affects the 30 percent of your FICO score that's based on the amounts you owe. The more you owe on all your accounts, the lower your credit score will be. A $150 unpaid dentist bill won't hurt your score as much as a $1,500 unpaid bill.